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采用脉冲微反技术研究了添加CeO2 和Co3 O4助剂对镍基催化剂上CH4积碳和CO2 消碳性能的影响 ,并用BET ,TGA ,XPS及CO2 TPSR等技术对催化剂进行了表征 .结果表明 ,添加CeO2 可以提高活性原子Ni0 中d电子的密度 ;Ni0 原子中d电子密度的增加在一定程度上抑制了CH4分子中C H键σ电子向d轨道的迁移 ,降低了CH4裂解积碳性能 ;同时加强了Ni0原子d轨道向CO2 空反键π轨道的电子迁移 ,促进了CO2 分子的活化 ,提高了CO2 的消碳活性 .助剂Co3 O4的添加则促进CH4的裂解积碳 ,抑制了CO2 的消碳 .分析表明 ,活性金属与半导体助剂之间存在的金属 半导体相互作用是影响这种机制的主要因素 .
The effect of adding CeO2 and Co3 O4 promoters on the carbon deposition and carbon dioxide emission of CH4 on nickel-based catalysts was studied by pulsed micro-reversal technique. The catalysts were characterized by BET, TGA, XPS and CO2 TPSR techniques. The addition of CeO2 can increase the density of d electrons in the active atom Ni0. The increase of d electron density in Ni0 atoms can inhibit the migration of CH bond σ electrons to d orbitals and reduce the carbon deposition of CH4 to a certain extent. The electron transfer from the orbital of Ni0 atom to the π orbit of CO2 vacancy bond promotes the activation of CO2 molecules and enhances the carbon elimination activity of CO2.The addition of promoter Co3 O4 promotes the cleavage of carbon in CH4 and inhibits the elimination of CO2 Carbon analysis shows that the interaction of metal semiconductors existing between active metal and semiconductor additive is the main factor affecting this mechanism.